Process for the production of ferroboron



Patented June 26, 1934 UNITED STATES PATENT OFFICE,

PROCESS FOR THE PRODUCTION OF FERROBORON Ernst Pokorny, Leipzig. and Hellmuth Seliger,

Bitterfeld,

Germany, assignors to I. G. Farbenindustrie Akticngesellschaft, Frankfort-onthe-Main, Germany No Drawing. Application March 24, 1933, Serial No. 662,642. In Germany April 6, 1932 4 Claims. (01. 75-17) Moreover, even in this case, no regulus is obtained, the reduced metal merely remaining in the refractory slag in the form of flakes.

The present invention aims at obtaining ferroboron without difliculty in the form of a welldefined regulus, which is practically free from aluminium, by the alumino-thermic reduction of boracite. To this .,end, according to the invention, a mixture of boracite and iron oxide (magnetite) is caused to react with an aluminiummagnesium alloy in the presence'of an oxidising agent such as potassium chlorate.

Whilst in the case of smaller batches it is advantageous to employ an alloy having a relatively high magnesium content (i. e. between about 30- and 60 percent of magnesium) for the reduction, it has been found with largerbatches, that the use of alloys richer in aluminium produces an increase in the yield without running the risk, in

the latter case, of the regulus being contaminated by any appreciable amount of aluminium.

n the other hand, when using aluminium alone, the reaction proceeds only sluggishly even in the presence of considerable quantities of potassium chlorate and a part of the reduced metal remains distributed through the slag. Moreover, it is of advantage to employ a certain excess of boracite since this facilitates the production of a more mobile slag, thus permitting the regulus tobe formed undisturbed. The amount of aluminiummagnesium alloy employed in carrying out the invention is advantageously so calculated that it is suflicient both for the decomposition of the potassium chlorate and for the reduction of the whole of the magnetite together with about 80 to 90 percent of the boracite.

.(7) 6.350 lrg. boracite (10 percent excess) The following comparative examples illustrate the influence of the various feature sof the hereindescribed process on the course of the reaction:

Reaction mixture Remarks (1) 144 g. boracite 104 g. magnetite..-" Does not react.

89.7 g. Al-granules 144 botacite }Reacti0n' sluggish flakes in 104 g. magnetite 103.1 g. Al-Mg-alloy 50/50 the no regulus' Reaction proceeds slowly,

144 g. boracite 104 g. magnetite- 139.7 g. Al-granules. 114 g. potassium chlorate ules in the slag. Aluminium content of regulus: 24.7 percent; boron content of regulus: 18.3 percent. Yield: 27.4 percent (exclusive of granulw).

(4) 144 g. be aclte 104 g. magnetite 131.5 g. Al-Mg-alloy 87 g. potassium chlorate (35 percent) um content of regulus: 9.6 percent; boron content of regulus: 20.4 percent; 7 yield: 68.0 percent.

JRglf-Ctloll vigorous, regulus,

Reaction vigorous, regulus,

aluminium content of regulus: 4.3 percent; boron content of regulust 20.7 percent; yield: 39.5 percent.

() 159 g. boracite (10 percent excess). 104 g. magnetitm 135.4 g. Al-Mg-elloy 70/30 79 g.- potassium chlorate ('percent) (6) 166 g. boracite (15 percent excess). Reaction vigorous, regulns;

104 g. magnetitealuminium content of regu- 123.7 g. Al-Mg-alloy /50.. lus: 0.6 percent; boron con- 41 g. potassium chlorate (15 pertent oi regulus: 19.6 percent)- cent; yield: 34.1 percent.

Reaction vigorous, regulus,

5.550 kg. magnetite 5.700 kg. Al-Mg-alloy 9010 3.600 kg. potassium chlorate (30 per cent) lus: 0.44 percent; boron content of regulus: 15.40 percent; yield: 58.8 percent.

In Examples 1 to 4, the amount of the reducing agent is so calculated that it is theoretically sumcient for the complete reduction. In- Ex-- amples 5 and 6, however, it is so calculated that 10 percent or 15 percent of the boracite remains unreduced. Example '7 is illustrative of the use of an alloy containing 90 percent of aluminium and 10 percent of magnesiumfor larger batches.

In carrying out the invention, it is also possible to replace the boracite by corresponding mixtures of the components B203, MgO and MgClz, or mixtures of boric acid with other a1- kaline earth oxides or chlorides.

We claim:-

regulus, nevertheless grenaluminium content of regu- 3. A process for the production of 'reguline ferroboron which -comprises causing a mixture of boracite and ferric oxide to react aluminothermically with an aluminium magnesium alloy in the presence of an alkali metal chlorate.

4. A process for the production of reguline Ierroboron which comprises causing a mixture of boracite and iron oxide to react alumino-thermically with an alloy containing between about 10 and about 60 per cent of magnesium, the remainder being aluminium, in the presence of an oxidizing agent.

ERNST POKORNY. I-IELLMUTH SEL'IGER. 

